Our long-term goal is to develop an effective vaccine to treat, and possibly to prevent, malignant melanoma. As part of this process, we seek to improve the potency of an existing melanoma vaccine which has shown promising results in clinical trials. The goal of this proposal is to evaluate whether this can be accomplished by encapsulating the vaccine together with IL-2 into liposomes. Our specific aims are: 1) To conduct a clinical trial to determine whether the potency of a polyvalent melanoma antigen vaccine can be increased by encapsulating the vaccine together with IL-2 into liposomes. Sequential groups of patients with disseminated melanoma will be treated with melanoma vaccine encapsulated into liposomes alone or together with different doses of IL-2. One week following 4 vaccine immunizations, antimelanoma antibody and cellular immune responses in the different groups will be compared; 2) determine the optimal biologic dose of IL-2 that maximally potentiates vaccine-induced immune responses; 3) evaluate the clinical effectiveness and; 4) the toxicity of this treatment. Successful completion of this work will provide basic immunological information necessary to rationally improve the effectiveness of melanoma vaccines, and may lead to improved treatments for the primary and secondary prevention of this cancer. More generally, the findings may provide means of augmenting the immunogenicity of vaccines for other cancers and for infectious diseases.